2015 is on track to be the warmest year on record, topping 2014.

With every passing month, the arguments for inaction on climate change are melting away faster than glaciers in Alaska. Let’s take them one at a time.

Argument No. 1: The science is uncertain. Actually, it’s not. An overwhelming majority of climate scientists agree that human activity is warming the planet. In fact, based on global surface temperatures, 2015 is on track to eclipse 2014 as the warmest year on record. This past summer was the hottest in recorded history, topping 2014 and even 1998, which featured an El Nino-driven spike that has allowed skeptics to claim, misleadingly, that temperatures haven’t increased much since then.

Argument No. 2: OK, the science is compelling, but other countries aren’t doing anything about their greenhouse gas emissions, so the U.S. shouldn’t bother. This assertion once held a kernel of truth, but it doesn’t any more. Ahead of international climate talks in Paris at the end of next month, China, the European Union, Brazil and India have all made new pledges to address global warming.

Of these, China, the world’s biggest source of carbon emissions, is by far the most important. Driven as much by short-term concerns about choking urban pollution as by long-term concerns about the planet, the Chinese have pledged to implement a carbon-trading plan in 2017 and have their emissions peak by about 2030. This creates the ironic situation in which the communist Chinese are adopting a market-based approach to curb carbon emissions, while the Obama administration — faced with an intransigent Republican-controlled Congress — has to pursue top-down strategies that rely on government mandates.

Argument No. 3: Efforts to control emissions will tank the economy. The "do nothing" crowd focuses on how efforts to limit carbon emissions will raise electric rates. In areas that rely primarily on coal-burning power plants, that could well happen. But coal is already being displaced by cheaper, cleaner natural gas. And the critics ignore the costs, such as higher charges for air conditioning and storm damage, of doing nothing about climate change.

Annual insurance losses from extreme weather events, adjusted for inflation, have increased from about $10 billion in the 1980s to about $50 billion in the past decade. Lloyd’s of London estimates that rising sea levels at the tip of Manhattan increased losses from Superstorm Sandy by 30% in New York alone. No wonder that so many businesses, other than those in the fossil fuel industry, are taking climate change seriously.

To the extent that there’s good news on the climate front, it’s that the world is starting to respond with the sort of urgency the threat requires. Pope Francis has added an important moral dimension to the debate. Renewable energy sources, particularly solar, are becoming more competitive. The Paris pledge drive for emissions reductions is getting important commitments from the key players.

Whether all this will be enough to prevent catastrophic warming and disruption remains uncertain. What is certain, however, is that the case for denial and delay is growing weaker all the time.

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